This invention relates generally to rolling mills, and more particularly to an improved means for supporting large cylindrical product coils during the transfer thereof from one location to another.
In the past, it has been the practice in rolling mills to transfer product coils by means of hook carrier systems. Such systems include large generally C-shaped hooks which are suspended from an overhead power-free conveyor. The hooks have horizontal support arms which extend axially through the "eyes" of the coils. Experience has shown that as a result of their being transported on hook carriers, the coils undergo damaging distortions commonly referred to as "horse-collaring" and "fanning-out."
"Horse-collaring" is the term given to the condition which occurs when a coil hangs from the horizontal arm of a hook and the weight of the hanging coil rings compresses and reduces the wall thickness of the portion of the coil wall contacted by the support arm, thus adding to the wall thickness at the bottom of the coil. The top wall of the coil becomes dense and the bottom becomes loose, which creates a very poor condition for subsequent coil compaction.
"Fanning-out" is the term given to describe the condition at the ends of a coil as it is carried on a horizontal support arm extending through the coil eye. The weight of the coil is supported by the horizontal arm which creates friction between the surface of the arm and the rings in contact therewith. This friction in turn restrains the upper portion of the coil from spreading out or extending. The forearm of the hook also tends to prevent the coil from expanding in one direction. However, the bottom portion of the coil is loose and free to expand. When the lower portion wall thickness is increased due to horse-collaring, the unrestrained lower portion expands end-wise forcing the rings outward at the lower extremities of the coil. This condition causes the coil to assume a "banana" shape. When the two extremities of a coil are not parallel, and the walls of the coil are not of uniform cross-section, density difficulties are encountered when compacting, and the banded coil often assumes a non-cylindrical shape.
The primary object of the present invention is to avoid the above-mentioned problems by providing a different and improved apparatus for supporting product coils during the transfer thereof from one location to another.